The present invention relates to the field of fretting machines. The present inventors presented a paper at The Symposium on Structural Integrity of Aging Aircraft, ASME WAM, San Francisco, on Nov. 12, 1995, entitled "Contribution of Fretting to the Fatigue and Corrosive Deterioration of a Riveted Lap Joint." As stated in the paper, the contacting parts of cyclically loaded, riveted connections present at the skin surface of an aircraft for example, are subject to fretting: small, repeated relative rubbing motions. This fretting produces wear, and can promote fatigue and corrosive damage which foreshortens riveted joint life, to in turn increase the risk of a detrimental aircraft malfunction.
In the experiments extensively described in the aforesaid paper, incorporated by reference herein, fretting of a sample riveted aluminum lap joint was produced by a novel fretting machine, also described in the paper, which is the subject of the present invention. This machine can move the sample through very small, controllable amplitudes and can accurately control rubbing forces applied to the sample.